Articulating Ladder, 17-Ft.17', articulating ladder, strong, safe, versatile, innovative features dual pin hinge & easy to use rock locks for quick adjustment, tip & glide wheels make it easy to move, can be used in many unique configurations up to 33, a frame, extension, staircase & 90 degree ladder, velocity trestle brackets sold separately to form a trestle & plank scaffolding system, constructed of a special alloy that makes it 20% lighter, wide flared legs, aerospace grade